24 BOTANY. feelings on being somewhat unexpectedly brought face to face with this peculiar vegetation would be futile, as no point of comparison appears to offer. The giant Cereus occupies the hill-sides which have a southern and southeastern exposure, towering up to a height of from 30 to 50 feet. Fouquieria, with its leafless, wandlike trunk, and its tip of scarlet flowers. Agave Palmeri and Parryi, and various species of Dasylirium, dry, rigid skeletons of plants without the living green; Canotia, a tree 20 feet high, a foot in diameter, with green branches provided with stomata, but no leaves, all go to complete this desolate floral landscape While the Mimosm, AcacicB, and CaliandrcB, rising to the dignity of trees or dwarfed to mere underbrush, inhabit the less dry hillsides and ravines, but still by their small leaves and hardened tissues show that they too have the impress of the dry, hot air about them. What the vegetation and climate of this valley may once have been we have now no means of certainly knowing. It is, however, in the highest degree probable that the process of desiccation, which has long been taking place in portions of New Mexico, is going on here. Along the higher bluffs back from the river, and far away from any chance of irriga¬ tion, one still sees the ruins of ancient pueblos, and in places traces of agricultural operations. Barren as the soil appears in its present dried condition, it has the capacity for production of luxuriant crops of corn, barley, cabbage, onions, potatoes, and watermelons where water can be furnished, as the garden at old Fort Goodwin proves, and as the Mexican Pueblo Viejo, some twenty miles further up the river, amply confirms. Leaving here an altitude of less than 3,000 feet, we again begin the ascent over a rolling country, and reach some twenty miles to the south an altitude of '1,833 feet at New Camp Grant. North of this. Mount Graham rises out of the plain, and attains an altitude of 10,357 feet. It is stated by Mr. Gilbert* to be made up on its northeastern face of gneissic rocks and a syenite, the great mass being probably metamorphic. As a single isolated centre, it presented more novelties than any other spot visited by us. Picea Engelmanni-was found even so far south. I have elsewhere called attention to the number of more northern forms that we obtained from near its summit. * Vol. iii, 509, Wlieeler's Eeport.